Acioa dolichopoda (Prance) Sothers & Prance, 2014

Sothers, Cynthia, Prance, Ghillean T., Buerki, Sven, Kok, Rogier De & Chase, Mark W., 2014, Taxonomic novelties in Neotropical Chrysobalanaceae: towards a monophyletic Couepia, Phytotaxa 172 (2), pp. 176-200 : 179-180

Acioa dolichopoda (Prance) Sothers & Prance , comb. nov.

Basionym: Couepia dolichopoda Prance (1974a: 302) . Type:— PERU. Loreto: Varadura de Mazán, from Río Amazonas to Río Napo , 21 August 1972, Croat 19382 (holotype NY!, isotypes G!, INPA!, MO!, RB!) .

Illustrations:— Prance (1974a: 303, 2001b: 26).

Distribution and habitat: —Western Amazonia in Colombia, Peru and Brazil. In terra firme forests from 100– 300 m.

Conservation status: —This species is here assessed as near threatened, NT ( IUCN 2001). Although Acioa dolichopoda occurs over an extensive range and is locally abundant in Colombia ( Rozo et al. 2009), it is less widespread than A. longipendula , and occurs in only a few localities in Colombia, Peru and in western Amazonian Brazil. This species was assessed as near threatened, NT (VU) for Colombia ( Calderón et al. 2002).

Selected specimens examined: — COLOMBIA. Amazonas: Correg. de Puerto Santander, La Chorrera , 7 km SW of Araracuara, 25 November 1993, Cárdenas et al. 4220 ( COAH, K!, NY!) . Caquetá: Río Messay , 16 March 1976, Roa 365 ( COL!, INPA!) . PERU. Loreto: Maynas Prov., Caserío Mishana, Río Nanay , 18 November 1981, Ruíz & Murphy 178 ( K!, MO!, NY!) ; Estac. Biol. Callicebus, Río Nanay –Mishana , 31 December 1981, Vásquez et al. 2788 ( MO!, NY!) ; near Brillo Nuevo, Río Yaguayaca , 8 November 1977, Gentry & Revilla 20385 ( MO!, NY!) . BRAZIL. Amazonas: Mun. de Amaturá, São Domingos , Rio Solimões , 21 November 1986, Daly et al. 4387 ( INPA!, NY!) ; Rio Javari , behind Estirão do Equador , 10 August 1973, Lleras et al. P 17294 ( FHO!, INPA!, NY!) ; Carauari, Rio Juruá , 30 June 1980, Silva et al. 452 ( INPA!, MG!, NY!, RB!) .

Notes: — Acioa longipendula and A. dolichopoda are known in the Amazon region for their fruits, the seeds of which are rich in oils and used locally for cooking. These two species were unique in Couepia s.l. as the only flagelliflorous, red-flowered and bat-pollinated species in the genus; they were also the only two species in the genus with fleshy leaves, like Acioa but unlike those of Couepia s.l. Both species have similar floral morphologies but display distinct characters, such as receptacle shape and stamens.

Acioa is a small South American genus previously comprising four species. Leaf, floral and fruit morphological characters easily distinguish Acioa from Couepia . The morphological synapomorphies shared by A. longipendula and A. dolichopoda and other members of Acioa include the fleshy, glabrous leaves with widely spaced secondary venation, the unequal calyx lobes (actinomorphic in Couepia ), a distinct pair of sessile glands on each of the calyx lobes (absent in Couepia ), stamens unilaterally arranged around the receptacle, the number of stamens varing from 10–20(–32) (32 in A. longipendula , in two semi-circles), and unilocular ovary positioned at the mouth of the receptacle (as in Couepia ).

The most notable feature of Acioa , stamens fused into a ligule, which was Aublet’s defining character for the genus, is now found in only three of the species, A. guianensis Aublet (1775: 698) , A. somnolens Maguire (1951: 272) and A. schultesii Maguire (1951: 272) ; A. longipendula , A. dolichopoda and A. edulis Prance (1972b: 12) all have free stamens. Molecular results presented here support placement of A. edulis in Acioa and refute the idea of fused stamens as the main character in defining this genus.

When Prance (1972b) first described Acioa edulis from fruiting material alone, he oscillated between placing it in Acioa or Couepia , but described it under Acioa . Once flowering collections of A. edulis were made, he transferred it to Couepia ( Prance 1975) , since the flowers displayed free stamens, but later transferred it back to Acioa despite lacking the main feature of Acioa , the fused stamens ( Prance & White 1988). The fruit of A. edulis is also rich in oils and used regionally for cooking, as are those of A. longipendula and A. dolichopoda .

The newly delimited Acioa is less disjunct in distribution with the inclusion of Acioa longipendula and A. dolichopoda . Previously each species of Acioa occurred in restricted localities. Acioa schultesii is restricted to the upper Caquetá River region in Venezuela, A. edulis is confined to the region of Tefé and the Purus River of Brazil, A. longipendula is widely distributed throughout the Amazon basin and A. dolichopoda occurs in isolated localities in Colombia, Peru and in the western portion of the Brazilian Amazon region. Acioa guianensis and A. somnolens are known from only a few specimens; A. guianensis is found in French Guiana, Amapá State (northeastern part of the Brazilian Amazon) and in the Humaitá River region of Brazil, whereas A. somnolens is known only from French Guiana.